Stool



FIG. 1 is a perspective view of a stool in accordance with the new design;

FIG. 2 is a front elevational view thereof, a rear elevational view being a mirror image thereof;

FIG. 3 is a left side elevational view thereof, a right side elevational view being a mirror image thereof;

FIG. 4 is a top view thereof; and,

FIG. 5 is a front perspective view thereof.

The broken lines in the figures are for illustration purposes only and form no part of the claimed invention. 

The ornamental design for a stool, as shown and described. 